Application of halo polyhydroxy polyurethane foam for the extraction of cobalt from cobalamin drugs and urine

Polyhydroxy polyurethane sorbent was modified by the addition of halogen atoms to its matrix to produce a new sorbent distinguished by high surface polarity, enhanced capacity, and improved stability in both acidic and alkaline media. Halo polyhydroxy polyurethane foam (X-PPF) was characterized by NMR, FTIR, UV–Vis, Raman spectroscopy, pH_ZCP values, and scanning electron microscopy images. Experimental studies have proven that X-PPFs have a great potential for the extraction and recovery of cobalt ions and this was attributed to the presence of halogen, phenolic, and urethane groups. The pH_ZCP value of X-PPFs was determined to be 0.91 and the maximum metal recovery was achieved at a pH range of 6–7. The kinetics of the process was best described by pseudo-second-order model (R² = 1). ΔH, ΔS, and ΔG values were calculated to be −57.2 kJ mol⁻¹, −172.6 J K⁻¹ mol⁻¹, and −5.8 kJ mol⁻¹, respectively. A perfect isotherm curve with zero intercept (0.002), good correlation (R² = 0.999), and capacity of 246.8 mg g⁻¹ was obtained.